登革熱發生流行風險及相關因子的探討

The risk and related factors of dengue outbreak

楊益昇(Yi-Sheng Yang)

指導教授 ： 張念台

國立屏東科技大學/農學院/植物保護系所/碩士(2007年)

https://doi.org/10.6346/NPUST.2007.00012

摘要

本研究主要分析屏東市登革熱 (Dengue fever) 流行之主要影響因子，並探討各地區病例發生流行之風險，先以實驗室內低溫10℃、13℃及15℃飼養屏東市埃及斑蚊 (Aedes aegypti (L.)) 和白線斑蚊 (Aedes albopictus (Skuse)) 觀察其生活史，以了解低溫對兩種斑蚊發育之影響，並利用斑蚊產卵誘引器 (ovitraps)，監測屏東市主要人口聚集地區不同季節之斑蚊族群消長與斑蚊之分布，再求取2002與2004年屏東市登革熱病例與氣候及病媒蚊密度等因子間的關係，同時估測登革熱發生流行之頻率及風險，以確定屏東市登革熱高風險發生流行區域，提供日後登革熱警訊發佈與防治重點等資訊之參考。低溫試驗中，埃及斑蚊只有在15℃下能完成世代，卵期、1、2、3、4齡幼蟲及蛹平均齡期分別為27.1±29.2、3.9±1.1、2.4±1.0、2.8±1.1、6.8±4.2及4.7±0.5日，由卵發育至成蟲平均需46.3±30.9日，累積死亡率為33%。白線斑蚊則在13℃之受測100粒卵中僅1隻雌蚊羽化，由卵至成蟲發育所需平均時間長達141日，而15℃所飼養卵、1、2、3、4齡幼蟲及蛹平均分別需42.1±44.2、5.3±2.4、3.6±2.6、4.4±5.4、7.5±5.1及4.6±0.8日，由卵發育至成蟲平均需64.9±22.8日，累
積死亡率為55%。2007年於屏東市設置產卵誘引器監測斑蚊發消長，調查期間出現2次高峰分別在6月23-25日及9月27-29日，每個產卵筒每次調查平均分別誘得15.4與19.7粒卵，平均誘集卵數與誘卵器陽性率(有蚊產卵比率)呈正相關性(r=0.79, p<0.05)，誘得卵數也與前3週之氣象因子平均均溫(r=0.59, p<0.05)、平均低溫(r=0.62, p<0.05)及累積雨量(r=0.48, p<0.05)有顯著正相關性，而誘得斑蚊種類則以白線斑蚊為主，各月皆占總誘得斑蚊數的80%以上。2002年與2004年屏東市登革熱發生與氣候因子關係的分析顯示，2002年每週登革熱確定病例數與前3個月前累積降雨量(r=0.86, p<0.05)、2個月前月均溫(r=0.58, p<0.05)與前1個月平均布氏指數(Breteau index) (r=0.63, p<0.05)有顯著的正相關性。2004年每週病例數則與前2個月的累積雨量(r=0.73, p<0.05)、月均溫 (r=0.58, p<0.05)及月平均布氏指數(r=0.78, p<0.05)也呈正相關性。綜合兩年的分析，病例發生前6-10週之雨量與前2-3週溫度上升，及前1-2月平均布氏指數增加情況下，確能造成登革熱病例的發生流行。另依據致病機率 (發生病例週數/流行期週數)、流行時間 (發生病例週數/發生病例之週峰數) 及傳播強度 (千人發病率/發生病例之週峰數) 將屏東市發生登革熱之里別分為不同流行風險型態，以2002年病例資料分析出有20里可列為高危險里別，2004年則有16里，而兩年均列高風險型態的里別則有12個里，再利用地理訊系統推估病例點之密度，可發現病例與病例間有相當群集的現象，這些病例群集區域與高危險里別可列為將來登革熱防治及衛教宣導的重點區域。

關鍵字

登革熱 ； 誘卵器 ； 埃及斑蚊 ； 白線斑蚊 ； 地理資訊系統

並列摘要

The purposes of this study were to analyze the risk and evaluate the influence of climate factors on the epidemics of dengue disease in Pingtung city, Taiwan. Initially, both dengue vector mosquitoes, i.e. Aedes aegypti (L.) and Aedes albopictus (Skuse), were reared in laboratory under 10, 13 and 15℃ conditions to illustrate the impact of low temperatures on the development of dengue vectors. The ovitraps were used to monitor the population and dynamics of Aedes mosquitoes in the densely residents areas of Pingtung. The dengue epidemic frequencies and risks, then, were evaluated through analysis of the relationships among various climate factors, changes of vector densities and dengue cases occurred in Pingtung city at 2002 and 2004. The Ae. aegypti can only survival at 15℃ in 3 tested low temperatures, and the mean duration of egg, l st to 4th instar larva and pupa were 27.1±29.2, 3.9±1.1, 2.4±1.0, 2.8±1.1, 6.8±4.2 and 4.7±0.5 days, respectively. The mean cumulative duration of immature stages was 46.3±30.9 days and mortality is 33% during this period. There was only 1 female adult of Ae. albopictus
eclosion out of 100 eggs tested at 13℃. The immature stage of this one was as long as 141 days. The developing times needed for egg, 1st to 4th instar larva and pupa of Ae. albopictus in 15℃ were 42.1±44.2, 5.3±2.4, 3.6±2.6, 4.4±5.4, 7.5±5.1 and 4.6±0.8 days, respectively. The mean duration of immature stage was 64.9±22.8 days and cumulative mortality was 55%. There were two population peaks of Aedes vectors found at 22-25 Jun and 27-29 Sep, with 15.4 and 19.7 of mean eggs collected per trap, respectively, during the field ovitrap surveillances at Pingtung city in 2007. The proportion of positive ovitrap (r=0.79, p<0.05) and climate factors, i.e. mean temperature (r=0.59, p<0.05), mean minimum temperature (r=0.62, p<0.05), and precipitation (r=0.48, p<0.05), of 3 weeks before surveillance provided the significant correlation with Aedes eggs collected per ovitrap. Also, over 80% of Ae. albopictus were found in monthly surveillance. The correlation analysis of dengue cases and various climate factors in 2002 and 2004 showed that dengue cases occurred in 2002 was positively related to precipitation of 1 month before (r=0.86, p<0.05), mean temperature of 2 month before (r=0.58, p<0.05), and Breteau index of 1 month before (r=0.63, p<0.05). The similar significant relationships also noted in dengue cases of 2004 and precipitation (r=0.73, p<0.05), monthly mean temperature (r=0.58, p<0.05), and Breteau index (r=0.78, p<0.05) of 2 month before. In general, the epidemic of dengue disease in Pingtung city apparently related to the increase of precipitation of 6-10 weeks before, the temperature of 2-3 weeks before as well as the mean Breteau index of 1-2 month before dengue epidemics. Also, the dengue frequency (weeks with cases/total epidemic weeks), epidemic period (weeks with cases/total of epidemic waves) and dengue intensity (incidence rate/total of epidemic waves) of each Li (the smallest administration unit) of Pingtung city were calculated and various risk type of dengue epidemic for each Li were classified accordingly. There were 12 Li that were decided as high risk area both in 2002 and 2004. The estimation of dengue density with GIS also showed the same results that dengue cases occurred aggregately in those high risk areas. Thus, the vector surveillance, source reduction and health education for the dengue prevention and control should focus on those areas.

並列關鍵字

dengue ； ovitrap ； Aedes aegypti ； Aedes albopictus ； GIS

參考文獻

1. 王正雄、黃基森、賴健榮。1990。屏東縣琉球鄉應用魚類生物防治登革熱病媒蚊初步試驗報告。高雄醫誌　6：382-388。

3. 行政院衛生署。1988。民國七十七年台灣地區登革熱流行概況。疫情報導　4：87-89。

5. 行政院衛生署疾病管制局 編。2002。登革熱病媒蚊密度測定訓練教材。行政院衛生署。臺北。39頁。

6. 行政院衛生署疾病管制局。2004。台灣地區埃及斑蚊分布鄉鎮現況。台北市：疾病管制局。2006年9月10日取自:

7. 吳民惠、黃高彬、蔡季君、吳宗樹、黃彥彰、金傳春。2005。2001-2003年台灣登革熱/登革出血熱的流行病學探討。台灣衛誌　24：452-459。